Smart conditioner rinse station

ABSTRACT

A method and apparatus for monitoring polishing pad conditioning mechanisms is provided. In one embodiment, a semiconductor substrate polishing system includes a rinse station, a polishing surface, a conditioning element, and a conditioning mechanism. The conditioning mechanism selectively positions the conditioning element over the polishing surface and over the rinse station. At least one sensor is provided and is configured to detect a first position and a second position of the conditioning element when disposed over the rinse station.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application claims benefit of U.S. Provisional ApplicationSer. No. 60/684,690, filed May 26, 2005, which is hereby incorporated byreference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention generally relate to a chemicalmechanical polishing system. In particular, embodiments of the presentinvention relate to a method and apparatus for monitoring a polishingsurface conditioning mechanism of a chemical mechanical polishingsystem.

2. Description of the Related Art

Chemical mechanical polishing is one process commonly used in themanufacture of high-density integrated circuits. Chemical mechanicalpolishing is utilized to planarize a layer of material deposited on asemiconductor substrate by moving the substrate in contact with apolishing surface while in the presence of a polishing fluid. Materialis removed from the surface of the substrate that is in contact with thepolishing surface through a combination of chemical and mechanicalactivity.

In order to achieve desirable polishing results, the polishing surfacemust be periodically dressed, or conditioned. One type of conditioningprocess, typically performed on the polyurethane polishing padstraditionally utilized in chemical mechanical polishing, is configuredto restore the fluid retention characteristics of the polishing surfaceand to remove embedded material from the polishing surface. Another typeof conditioning process, typically performed on fixed abrasive polishingmaterials, is configured to expose abrasive elements disposed withinstructures comprising the abrasive polishing material, while removingasperities from the upper surface of the polishing material and levelingthe structures comprising the polishing surface to a uniform height.

In one embodiment, a polishing surface conditioner includes areplaceable conditioning element, such as a diamond disk, coupled to aconditioning head that is movable over the polishing surface. Theconditioning element is lowered into contact with the polishing surfacewhile being rotated. The conditioning head is generally swept across therotating polishing surface to allow the conditioning element tocondition a predefined area of the polishing surface.

Conventional conditioners commonly utilize diaphragms within theconditioning head to control the elevation of the conditioning element.A cavity behind the diaphragm is generally pressurized to lower theconditioning element and press it against the polishing surface of thepolishing pad during conditioning. Upon completion of conditioning, thecavity is vented, allowing the conditioning element to retract,typically assisted by an upward spring bias.

The pressurization and the venting of the cavity causes the diaphragm torepeatedly stretch and relax. In addition, the raising and lowering ofthe conditioning element further applies stress to the diaphragm.However, the elastomeric diaphragm, like all other elastomeric materialshave a finite life. Without repair or replacement, the eventualdeterioration of the diaphragm leads to poor conditioning. To preventthe inevitable deterioration, the diaphragm is typically replaced on aset interval, for example after a preselected number of conditioningcycles. However, the conventional method is inefficient. Sometimes, thediaphragm will be replaced while it is still in good condition, causingunnecessary downtime and increasing costs. At other times, a diaphragmin poor condition is not replaced soon enough, causing poor conditioningof the pad.

Therefore, there is a need for a method and apparatus for monitoring padconditioning mechanisms.

SUMMARY OF THE INVENTION

A method and apparatus for monitoring polishing pad conditioningmechanisms is provided. In one embodiment, an apparatus is provided formonitoring a conditioner that includes a sensor arranged to detect aperformance attribute of a conditioning element when the conditioningelement is not engaged with a processing pad. Performance attributes mayinclude at least one of downforce, power transmission or condition ofthe conditioning surface, among other attributes that may affectconditioning performance.

In another embodiment, a semiconductor substrate polishing systemincludes a rinse station, a polishing surface, a conditioning element,and a conditioning mechanism. The conditioning mechanism selectivelypositions the conditioning element over the polishing surface and overthe rinse station. At least one sensor is provided and is configured todetect a first position and a second position of the conditioningelement when disposed over the rinse station.

In another embodiment, a semiconductor substrate polishing system havinga polishing surface and a conditioning mechanism that is movable betweena conditioning position disposed over the polishing surface and anon-conditioning position to the side of the polishing surface. Theconditioning mechanism has a conditioning element for conditioning thepolishing surface. A sensor is provided and is configured to detect aperformance attribute of the conditioning element while in thenon-conditioning position.

In another aspect of the invention, a method for characterizing aconditioning mechanism is provided. In one embodiment the methodincludes sensing a metric of a performance attribute of the conditioningmechanism and determining from the sensed metric is within a processwindow.

In another embodiment, a method for characterizing a component of aconditioning mechanism includes actuating a conditioning element of theconditioning mechanism to move between a first position and a secondposition. Next, the time required to actuate the conditioning elementbetween the first position and the second position is analyzed.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is a top view of an illustrative polishing system having oneembodiment of a rinse station for a conditioning mechanism;

FIG. 2 is a sectional side view of one embodiment of the conditioningmechanism and rinse station of FIG. 1;

FIGS. 3A and 3B respectively depict a side and top view of oneembodiment of a rinse station;

FIGS. 4A, 4B and 4C depict methods of use of the rinse station; and

FIG. 5 is a chart depicting sensor timings for the rinse station.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements from one embodiment may bebeneficially incorporated in other embodiments without furtherrecitation.

DETAILED DESCRIPTION

FIG. 1 is a top view of an illustrative polishing system 100 having oneembodiment of a rinse station 135 of the present invention. Thepolishing system 100 generally includes a factory interface 104, acleaner 106 and a polisher 108. Two polishing systems that may beadapted to benefit from the invention is a REFLEXION® chemicalmechanical polishing system and the REFLEXION LK Ecmp™, both availableavailable from Applied Materials, Inc., located in Santa Clara, Calif.Another polishing system that may be adapted to benefit from theinvention is described in U.S. Pat. No. 6,244,935, issued Jun. 12, 2001,to Birang, et al., entitled, “Apparatus and Methods for ChemicalMechanical Polishing with an Advanceable. Polishing Sheet,” which isincorporated by reference in its entirety.

A controller 160 is provided to facilitate control and integration ofthe system 100. The controller 160 typically comprises a centralprocessing unit (CPU), memory, and support circuits (not shown). Thecontroller 160 is coupled to the various components of the system 100 tofacilitate control of, for example, the planarizing, cleaning, andtransfer processes.

In one embodiment, the factory interface 104 includes a first, orinterface, robot 110 adapted to transfer substrates from one or moresubstrate storage cassettes 112 to a first transfer station 114. Asecond robot 116 is positioned between the factory interface 104 and thepolisher 108 and is configured to transfer substrates between the firsttransfer station 114 of the factory interface 104 and a second transferstation 118 disposed on the polisher 108. The cleaner 106 is typicallydisposed in or adjacent to the factory interface 104 and is adapted toclean and dry substrates returning from the polisher 108 before beingreturned to the substrate storage cassettes 112 by the interface robot110.

The polisher 108 includes at least one polishing station 126 and atransfer device 120 disposed on a base 140. In the embodiment depictedin FIG. 1, the polisher 108 includes three polishing stations 126, eachhaving a platen 130 that supports a polishing material 128 on which thesubstrate is processed.

The transfer device 120 supports at least one polishing head 124 thatretains the substrate during processing. In the embodiment depicted inFIG. 1, the transfer device 120 is a carousel supporting one polishinghead 124 on each of four arms 122. One arm 122 of the transfer devicesis cutaway to show the second transfer station 118. The transfer device120 facilitates moving substrates retained in each polishing head 124between the second transfer station 118 and the polishing stations 126where substrates are processed. The polishing head 124 is configured toretain a substrate while polishing. The polishing head 124 is coupled toa transport mechanism that is configured to move the substrate retainedin the polishing head 124 between the transfer station 118 and thepolishing stations 126. One polishing head that may be adapted tobenefit from the invention is a TITAN HEAD™ substrate carrier, availablefrom Applied Materials, Inc.

The second transfer station 118 includes a load cup 142, an input buffer144, an output buffer 146 and a transfer station robot 148. The inputbuffer 144 accepts a substrate being transferred to the polisher 108from the second robot 116. The transfer station robot 148 transfers thesubstrate from the input buffer 144 to the load cup 142. The load cup142 transfers the substrate vertically to the polishing head 124, whichretains the substrate during processing. Polished substrates aretransferred from the polishing head 124 to the load cup 142, and thenmoved by the transfer station robot 148 to the output buffer 146. Fromthe output buffer 146, polished substrates are transferred to the firsttransfer station 114 by the second robot 116 and then transferredthrough the cleaner 106. One second transfer station that may be adaptedto benefit from the invention is described in U.S. Pat. No. 6,156,124,issued Dec. 5, 2000 to Tobin, entitled, “Wafer Transfer Station for aChemical Mechanical Polisher,” which is incorporated by reference in itsentirety.

A polishing fluid delivery system 102 includes at least one polishingfluid supply 150 coupled to at least one polishing fluid delivery armassembly 152. Generally, each polishing station 126 is equipped with arespective delivery arm assembly 152 positioned proximate to arespective platen 130 to provide polishing fluid thereto duringpolishing. In the embodiment depicted in FIG. 1, the three polishingstations 126 each have one delivery arm assembly 152 associatedtherewith.

The platen 130 of each polishing station 126 supports a polishingmaterial 128. During processing, the substrate is held against thepolishing material 128 by the polishing head 124 in the presence ofpolishing fluid provided by the delivery system 102. The platen 130rotates to provide at least a portion of the, polishing motion impartedbetween the substrate and the polishing material 128. Alternatively, thepolishing motion may be imparted by moving at least one of the polishinghead 124 or polishing material 128 in a linear, orbital, random, rotaryor other motion.

The polishing material 128 may be comprised of a foamed polymer, such aspolyurethane, a conductive material, a fixed abrasive material orcombinations thereof. Fixed abrasive material generally includes aplurality of abrasive elements disposed on a flexible backing. In oneembodiment, the abrasive elements are comprised of geometric shapesformed from abrasive particles suspended in a polymer binder. Thepolishing material 128 may be in either pad or web form.

A conditioning mechanism 134 is disposed proximate each polishingstation 126 and is adapted to dress or condition the polishing material128 disposed on each platen 130. Each conditioning mechanism 134 isadapted to move between a position clear of the polishing material 128and platen 130 as shown in FIG. 1, and a conditioning position over thepolishing material 128. In the conditioning position, the conditioningmechanism 134 is actuated to engage the polishing material 128 and worksthe surface of the polishing material 128 to a state that producesdesirable polishing results. In the position clear of the polishingmaterial 128 and the platen 130, the conditioning mechanism 134 ispositioned to engage with the rinse station 135.

FIG. 2 is a sectional view of one embodiment of the conditioningmechanism 134 engaged within the rinse station 135. The conditioningmechanism 134 generally includes a head assembly 202 coupled to asupport member 204 by an arm 206. The support member 204 is disposedthrough the base 140 of the polisher 108. Bearings 212 are providedbetween the base 140 and the support member 204 to facilitate rotationof the support member 204. An actuator 210 is coupled between the base140 and the support member 204 to control the rotational orientation ofthe support member 204. The actuator 210, such as a pneumatic cylinder,servo motor, motorized ball screw, harmonic drive or other motioncontrol device that is adapted to control the rotational orientation ofthe support member 204, allows the arm 206 extending from to the supportmember 204 to be rotated about the support member 204, thus laterallypositioning the head assembly 202 relative to the polishing station 126.A conditioning element 208 is coupled to the bottom of the head assembly202 and may be selectively pressed against the platen 130 to conditionthe polishing material 128.

The elevation of the conditioning element 208 is generally controlled bypressurizing an expandable cavity 290 partially bounded by a diaphragm240 disposed in head assembly 202. A spring 242 disposed in the headassembly 202 provides an upward bias that assists in the retraction ofthe conditioning element 208 when the cavity 290 behind the diaphragm240 is vented or evacuated. Examples of conditioning mechanisms suitablefor use with the present invention are described in U.S. patentapplication Ser. No. 10/411,752, filed Apr. 10, 2003 by Lischka, et al.,entitled “Conditioner Mechanism for Chemical Mechanical Polishing,” andU.S. Pat. No. 6,572,446, issued Jun. 3, 2003 to Osterheld, et al.,entitled “Chemical Mechanical Polishing Pad Conditioning Element withDiscrete Points and Compliant Membrane,” each of which are herebyincorporated by reference. Although the conditioning head assembly 202depicted in FIG. 2 shows a rolling diaphragm 240 and a spring 242, it iscontemplated that conditioning head assemblies 202 utilizing otheractuating mechanisms, such as full diaphragms, belts, springs,actuators, and the like, may be characterized in the rinse station 135,as further discussed below. Moreover, it is contemplated that teachingsdisclosed herein may be utilized to characterize components in otherprocessing equipment, for example, the diaphragms and/or bladders in thepolishing head 124, or other components subject to wear over its servicelife.

The support member 204 houses a drive shaft 214 that couples a motor216, disposed below the base 140, to a pulley 218 disposed adjacent afirst end 220 of the arm 206. A belt 222 is disposed in the arm 206 andoperably couples the pulley 218 and the head assembly 202, therebyallowing the motor 216 to selectively rotate the conditioning element208. The belt 222 is contemplated as any member adapted to transferrotational motion between the motor 216 and the head assembly 202.

A control fluid conduit 224 from a fluid control system 226 is routedthrough the support member 204 and arm 206, and is coupled to the headassembly 202. The fluid control system 226 includes a gas supply andvarious control devices (i.e., valves, regulators, and the like) thatfacilitate the application and/or removal of fluid pressure to thecavity 290 of the head assembly 202. In one embodiment, the fluidcontrol system 226 provides air or nitrogen to control the elevation ofthe conditioning element 208 relative to the platen 130 (or base 140),and to control the pressure applied by the conditioning element 208against the polishing material 128 during conditioning (e.g., down forceof the conditioning head).

The conditioning element 108 is moved to the rinse station 135 when notin use. The rinse station 135 generally includes a body 230, one or moresensors 250, and a rinse nozzle 234. In one embodiment, the body 230 isheld in position above the base 140 by a support 238. The body 230 maybe coupled directly to the support 238. Alternatively, the body 230 maybe coupled to the support 238 through a mounting plate 232. Having thebody 230 raised above the base 140 facilitates drainage of fluids andremoval of other debris as the conditioning element 208 is rinsed asdescribed further below.

The one or more sensors 250 are provided to detect a metric ofconditioner performance. Some metrics of conditioner performance thatmay be sensed include conditioner downforce, attributes of theconditioning surface, power transmission (such as for conditionerrotation), seal and diaphragm performance and rinse fluid flow, amongothers. In one embodiment, sensors 250 are configured to sense theposition of the conditioning element 208 at multiple predefinedpositions of extension with respect to the head assembly 202. Thesensors 250 may be positioned anywhere suitable for detecting theposition of the conditioning element 208 at the predefined locations.Alternatively, one or more of the sensors 250 may be located in aposition remote from the rinse station 135. For example, one or moresensors 250 may be positioned in or on the head assembly 202, the arm206, the base 140, or other location suitable for sensing the positionof the conditioning element 208 with respect to the head assembly 202.In the embodiment depicted in FIG. 2, at least one sensor 250 is coupledto the body 230.

The rinse nozzle 234 provides a cleaning fluid from a fluid source 236to rinse, or clean, the working surface of the conditioning element 208.The nozzle 234 is positioned to effectively rinse the conditioningelement 208 and/or other components of the head assembly 202. In oneembodiment, the rinse nozzle 234 is disposed to the mounting plate 232.

FIGS. 3A and 3B respectively depict side and top views of one embodimentof the rinse station 135. The body 230 of the rinse station 135 includesan arm 302 and a bracket 306. The arm 302 may be coupled to the mountingplate 232 in any suitable manner, for example, by a plurality of screws(not shown). The arm 302 includes a contoured inner edge 330 and a ledge304. The inner edge 330 is contoured to allow clearance of theconditioning element 208 when engaged with the rinse station 135 (asdepicted in FIG. 2). The ledge 304 provides a hard stop for theconditioning element 208 when lowered into the rinse station 135. Thus,when the conditioning element 208 is positioned in the rinse station135, the conditioning element 208 is disposed proximate the inner edge330 of the arm 302 and may contact the ledge 304 when lowered. The ledge304 is typically contoured to allow the conditioning element 208 to berinsed by the rinse arm 234 (i.e., the ledge 304 is cut away to exposesubstantially all of the bottom of the conditioning element 208.

Optionally, one of the sensors 250 for characterizing conditionerperformance may be a sensor 390 disposed in the ledge 304 suitable fordetecting a metric of conditioning downforce. Thus, as the conditioningelement 208 is actuated against the ledge 304, the sensor 390 mayprovide the controller with a metric indicative of downforce which maybe compared with an expected value or a process window. If the senseddownforce is outside of the process window and/or a value different thanan expedited value, the controller may flag the event, notify theoperator or interrupt processing operations. The data provided by thesensor 390 may also be used to trend performance to predict or monitorservice life. Moreover, the downforce sensor 390 will allow thedetection of seal and/or diaphragm leaks, pressure supply draft and thelike by providing data that enables the detection of force changes overtime.

Optionally, instead of providing characterizing information directly tothe controller 160, a dedicated PLC 292 or other computing device maymonitor the sensors 250. The PLC 292 may have an output coupled to thecontroller 160 to flag potential conditioner performance issues thathave been identified as triggers for the controller to halt and/or alterconditioning and/or substrate process.

Also depicted in the embodiment of FIG. 2 are one or more sensors 250that include a first sensor 312 disposed on the inner edge 330 of thearm 302, and a second sensor 316 is coupled to a bottom surface of thearm 302. The sensors 250 may comprise any suitable sensor for detectingthe position of the conditioning element 208. In one embodiment, thefirst sensor 312 is a break-through sensor configured to transmit andreceive a beam of light (as indicated by dashed line 314) for sensingwhen an interposing object (i.e., the conditioning element 208) ispositioned therebetween.

In one embodiment, the second sensor 316 is a proximity sensorpositioned beneath a portion 318 of the ledge 304. The proximity sensor,or second sensor 316, detects when the conditioning element 208 isdisposed within a predefined distance from or on the portion 318 of theledge 304.

The sensors 312, 316 are generally coupled to the PLC 292 or otherdevice suitable for recording the data obtained by the sensors such as astrip chart recorder or memory module. By detecting the position of theconditioning element 208 at various locations in the rinse station 135,a plurality of characterizations of the conditioning mechanism 134 maybe advantageously performed, as described in more detail below.

The bracket 306 is adjustably coupled to the arm 302 in any suitablemanner, for example, by a screw or bolt (not shown) disposed through anelongated slot 310. The adjustment of the bracket 306 allows alignmentof a support ledge 308 formed in the bracket 306 with the ledge 304 ofthe arm 302, thereby providing an extended support area for theconditioning element 208 of the head assembly 202 when positioned in therinse station 135. The extended support area prevents uneven forces frombeing applied to the components of the head assembly 202 when theconditioning element 208 is lowered and pressed against the ledge 304.

In another embodiment, the sensor 390 may be configured to provide ametric indicative of a surface condition of the conditioning element208. For example, the sensor 390 may be a roughness sensor formonitoring the surface condition of the conditioning element. In anotherexample, the sensor 390 may be a camera for visually monitoring thesurface condition of the conditioning element 208. It is contemplatedthat images from the surface of the conditioning element 208 may beelectronically analyzed to determine the state of the condition, such asmissing diamond or abrasives, and the like. It is also contemplated thatthe sensor 390 may be configured to provide a metric indicative of thecut rate the conditioning element 208.

The rinse nozzle 234 is positioned to supply a stream of rinsing and/orcleaning fluid to the bottom surface of the conditioning element 208and/or head assembly 202. In one embodiment, the rinse nozzle 234 iscoupled to the mounting plate 232 in a suitable manner, such as bythreaded engagement. The configuration and position of the nozzle 234 isselected to direct the flow of fluid to a desired location on theconditioning element 208 when the head assembly 202 is disposed in therinse station 135. The nozzle 234 is coupled to the fluid source 236. Itis contemplated that the rinse nozzle 234 may alternatively be coupledto different components of the polishing system 100, such as the base140, so long as it is disposed in a position suitable for delivering astream of rinsing and/or cleaning fluid to the conditioning element 208and/or head assembly 202.

Optionally, additional nozzles may be formed in the member 320 or otherlocation in the rinse station 135 and coupled to the fluid source 236.For example, in the embodiment depicted in FIGS. 3A and 3B, a secondnozzle 324 is formed in the mounting plate 232 and is positioned tospray rinsing and/or cleaning fluid along the periphery of theconditioning element 208 and/or the head assembly 202.

In one embodiment, one of the sensors 250 for characterizing theconditioner may be positioned to detect the flow of cleaning fluid intothe rinse station 135. For example, in the embodiment depicted in FIG.3B, a sensor 322, such as a flow sensor, may be interfaced with theconduits providing fluid to the nozzle 234 and configured to provide ametric of flow in the rinse station 135, thereby providing the PLC 292an indication whether the conditioning element 208 is being rinsed asexpected.

In yet another embodiment, one of the sensors 250 for characterizing theconditioner may be positioned to detect the rotational motion of theconditioning element. For example, in the embodiment depicted in FIG.2B, a sensor 252, such as a rotary sensor, may be interfaced with thebelt 222 and/or head assembly 202 or other component and configured toprovide a metric indicative of the rotation of the conditioning element208, thereby providing the PLC 292 an indication that the conditioningelement 208 rotating in a predetermined manner.

In operation, the conditioning mechanism 134 is rotated to place thehead assembly 202 and conditioning element 208 above the rinse station135. A cleaning fluid may be supplied from the nozzles 322 and 324 toremove any debris disposed on the surface of the conditioning element208 and/or head assembly 202 (for example, polishing slurries,particulate matter, and the like).

The conditioning element 208 may further be lowered into contact withthe ledges 304, 308 of the rinse station 135 via pressurization of thecavity 290 (depicted in FIG. 2). As the conditioning element 208 islowered, the PLC 292 records data corresponding to when the first sensor312 detects the position of the conditioning element 208 (e.g., when thebeam 314 is broken). The PLC 292 further records data corresponding towhen the conditioning element 208 contacts the ledge 304, as detected bythe second sensor 316.

By comparing the data recorded when the conditioning element 208 passesthe first sensor 312 and the second sensor 316, a time to move theconditioning element 208 downwards between a known distance (i.e.,between the sensors 312, 316) may be obtained. The time may be comparedto a predefined amount of time or the time may be charted over a periodof multiple cycles to monitor trends in the time to actuate theconditioning element 208 downwards.

Characterization of the conditioning elements movement relative therinse station 135 may also be obtained by utilizing one or moreparameters such as time between commencing the heat movementconditioning elements (i.e., the pressurization of the cavity 290),cavity pressure and/or rate of change at different elevations and thelike. Additionally, the bottom surface of the conditioner may bemonitored for cleanliness, damage and/or for wear. Furthermore,operational aspects of the conditioner, such as downforce, rotationalspeed, cut rate and cleanliness, which may be compared to a processwindow so that the conditioner may be recleaned or surface prior toconditioning the polishing surface, thereby preventing processabnormalities.

For example, FIG. 4A depicts a method 400 for monitoring a conditioningmechanism, described with reference to the apparatus depicted in FIGS. 2and 3A-B. The method 400 begins at step 402, where the conditioningelement 208 is lowered into the rinse station 135 by pressurizing thecavity 290. The method continues at step 404, where the time required tolower the conditioning element 208 into within a predetermined distanceof the ledge 304 is recorded. The recorded time may be the time betweencommencement of cavity pressurization and sensor trigger.

In one embodiment, step 404 includes substep 406, where a timer beginscounting when the first sensor 312 senses the conditioning element 208(e.g., when the conditioning element 208 breaks the beam of light 314between the emitter and receiver pair of the first sensor 312). Atsubstep 408, the timer stops counting when the second sensor 316 detectsthe conditioning element 208 on the ledge 304. Alternatively, a starttime may be recorded in step 406 and a stop time recorded in step 408,with the time required to lower the conditioning element 208 calculatedby subtracting the start time from the stop time.

In other embodiments, the sensors 312, 316 may detect alternatepositions of the conditioning element 208. For example, the sensors 312,316 or the method may be configured to record the time required to raisethe head assembly 202. Alternatively or in addition, the sensor 252 maybe utilized to detect the rotation of the conditioning element 208. Byrecording a time required to raise, lower, or rotate the conditioningelement 208, the condition of the diaphragm, springs, or othercomponents of the head assembly 202 of the conditioning mechanism 134may be monitored.

In another example, FIG. 4B depicts a method 410 for monitoring aconditioning mechanism, described with reference to the apparatusdepicted in FIGS. 2 and 3A-B. The method 410 begins at step 412, whenthe time required to lower the conditioning element 208 is stored, forexample, in a database. Next, at step 414, the time required to lowerthe conditioning element 208 is analyzed. The time required to lower theconditioning element 208 may be analyzed in many different ways. Forexample, at substep 416, the time required to lower the head assemblymay be charted over a plurality of cycles in order to determine ormonitor trends in the variation of the time required to lower theconditioning element 208. Alternatively or in combination, substep 418may be utilized to compare the time required to lower the conditioningelement 208 to a preselected threshold value.

Next, at step 420, a course of action is decided upon based on theanalysis of step 414. For example, at step 422, a decision may be madeto repair or replace the diaphragm 240 of the head assembly 202.Alternatively, the analysis may indicate that the diaphragm 240 is stillin acceptable condition and may be continued to be used, as depicted insubstep 424. The decision made in step 420 may be made in a variety ofways.

For example, in embodiments where the time required to lower theconditioning element 208 is charted over a plurality of cycles, as insubstep 416, the decision may be made based upon changes in the slope ofthe charted curve, which may indicate a more rapid deterioration in thecondition of the diaphragm 240. Alternatively, before substep 418 isused, a preselected threshold value may be utilized in comparison to thetime required to lower the conditioning element 208, such that if thetime required to lower the conditioning element 208 exceeds thethreshold value, it is indicative of the deterioration of the diaphragm240 to the point where its replacement is required.

It is contemplated that step 412 and substep 416 of the method 410 maybe omitted. For example, the method 410 may comprise merely comparingthe time required to lower the conditioning element 208 to a preselectedthreshold value, as in substep 418, without the need for reference toprevious values and thus, the need to store the time required to lowerthe conditioning element 208, or to chart the time over a plurality ofcycles.

FIG. 4C is a flow diagram of another method 440 for monitoring aconditioning mechanism. The method 440 begins at step 442 by detecting ametric indicative of a characteristic of the conditioning mechanism 134.The metric may be provided to the controller 160 and/or PLC 292 taskedwith monitoring conditioner function and/or performance from one or moreof the sensors as described above. At step 444, the metric and/orinformation derived from the sensor is analyzed. The analysis mayinclude determining if the characteristic is within a processing window,determining if maintenance is required, determining a wear rate of acomponent, determining an arrival of a need for maintenance based an awear rate, determining if the conditioning element 208 needsreplacement, determining if power transmission parts (e.g., belts,bearing, etc.) need service, should be re-cleaned determining if theconditioning element 208 should be re-cleaned, determining if thecleaning of the conditioning element is operating within specification,and determining if conditioning operations need to be suspended ormodified. It is contemplated that many other performance/conditionerhealth indicators may be monitored. At step 446, if the analysisindicates that the sensed metric is out of specification or outside aprocess window, corrective action is taken at step 448. Examples ofcorrective action include flagging a need for maintenance and/orcomponent replacement, adjusting downforce pressure, adjustingrotational speed, adjusting a pad conditioning routine for a change inconditioner cut-rate, unclogging a fluid line, re-cleaning theconditioning element, predicting a need for future maintenance, andflagging potential conditioning abnormalities, among others. If, at step446, the analysis indicates that performance is within specification,then the method returns to step 442 to continuing to monitoring theconditioning mechanism 134.

FIG. 5 depicts a graph of sensor timings showing additional variablesthat may be monitored, recorded, charted, and the like to furthercharacterize critical components of the conditioning mechanism 134. FIG.5 depicts the digital states, i.e., “on” or “off,” (along an axis 502)over time (along an axis 504) for the first sensor (line 506), secondsensor (line 508), and the pressure command (line 510).

The pressure command is the instruction to pressurize or exhaust thediaphragm 240 to raise or lower the conditioning element 208. The grapharbitrarily starts with the conditioning element 208 lowered anddisposed against the ledge 304. At time 520, the state of the pressurecommand is switched from off to on, correlating with a command to raisethe conditioning element 208. At time 522, the state of the secondsensor 316 changes from on to off, indicating that the conditioningelement 208 has begun to rise and is no longer on the ledge 304. At time524, the state of the first sensor 312 changes from off to on,indicating that the conditioning element 208 has passed the first sensor312.

The time period between the change in state of the pressure command andthe change in state of the second sensor 316 is labeled T1. T1 isindicative of the amount of time it takes between the issuance of thecommand to raise the conditioning element 208 and the lift off of theconditioning element 208 from the ledge 304. The time period between thechange in state of the pressure command and the change in state of thefirst sensor 312 is labeled T2. T2 is indicative of the amount of timeit takes between the issuance of the command to raise the conditioningelement 208 and the arrival of the conditioning element 208 at an upperposition proximate the first sensor 312. The time difference between T2and T1 is indicative of the amount of time actually required for theconditioning element 208 to travel between the lower position on theledge 304 and the upper position proximate the first sensor 312.

At time 526, the state of the pressure command is switched from on tooff, correlating with a command to lower the conditioning element 208.At time 528, the state of the first sensor 312 changes from on to off,indicating that the conditioning element 208 has begun to descend and isno longer proximate the first sensor 312. At time 530, the state of thesecond sensor 316 changes from off to on, indicating that theconditioning element 208 has contacted the ledge 304.

The time period between the change in state of the pressure command andthe change in state of the first sensor 312 is labeled T3. T3 isindicative of the amount of time it takes between the issuance of thecommand to lower the conditioning element 208 and the descent of theconditioning element 208 from the position proximate the first sensor312. The time period between the change in state of the pressure commandand the change in state of the second sensor 316 is labeled T4. T4 isindicative of the amount of time it takes between the issuance of thecommand to lower the conditioning element 208 and the arrival of theconditioning element 208 on the ledge 304. The time difference betweenT4 and T3 is indicative of the amount of time actually required for theconditioning element 208 to travel between the upper position proximatethe first sensor 312 and the lower position on the ledge 304.

Any one or a combination of these time periods may be monitored and/orcharted over time as described above with respect to FIGS. 4A and 4B inorder to determine whether the diaphragm 240 requires repair orreplacement. Alternatively, other motions may be monitored, such as therotation of the head assembly 202, in order to characterize thecondition of the desired critical components.

Thus, methods and apparatus for monitoring a conditioning mechanism areprovided. In one embodiment a smart rinse station is provided to cleanthe conditioning mechanism when not in use and to characterize criticalcomponents of the conditioning mechanism, such as a diaphragm, springs,and the like. The conditioning mechanism may be characterized over timeto detect trends or in comparison to preselected threshold values inorder to detect deterioration in the performance of the conditioningmechanism and to prevent poor conditioning. Although the above apparatusand methods are described with respect to a conditioning mechanism, itis contemplated that the above teachings may be modified for use inmonitoring and characterizing critical components in other systems aswell.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A semiconductor substrate polishing system, comprising: a polishingsurface; a conditioning element; a conditioning mechanism forselectively positioning the conditioning element over the polishingsurface; and at least one sensor positioned to sense an attribute of theconditioning mechanism, wherein the attribute is indicative ofconditioner performance.
 2. The system of claim 1, wherein the at leastone sensor is configured to detect a first position and a verticallyoffset second position of the conditioning element.
 3. The system ofclaim 1, further comprising: a rinse station laterally disposed from thepolishing surface, the conditioning mechanism further configured toselectively position the conditioning element proximate the rinsestation.
 4. The system of claim 3, wherein the rinse station furthercomprises: a rinse nozzle configured to spray a fluid on theconditioning element.
 5. The system of claim 1, wherein the at least onesensor is disposed in the rinse station.
 6. The system of claim 5,wherein the at least one sensor further comprises: a first sensorconfigured to detect a first position of the conditioning element; and asecond sensor configured to detect a second position of the conditioningelement.
 7. The system of claim 1, wherein the at least one sensor isconfigured to detect rotation of the conditioning element.
 8. The systemof claim 1, wherein the at least one sensor is configured to detectdownforce of the conditioning element.
 9. The system of claim 1, whereinthe at least one sensor is configured to provide a metric indicative ofa conditioning surface of the conditioning element.
 10. The system ofclaim 9, wherein the metric indicative of the conditioning surface is atleast one of cut-rate, cleanliness, conditioning element wear or damage.11. The system of claim 4, wherein the at least one sensor is configuredto provide a metric indicative of a fluid flow through the nozzle. 12.The system of claim 1 further comprising: a controller coupled to the atleast one sensor and containing instructions for characterizing healthof the conditioner.
 13. A semiconductor substrate polishing systemhaving a polishing surface, comprising: a conditioning mechanism movablebetween a conditioning position disposed over the polishing surface anda non-conditioning position to the side of the polishing surface, theconditioning mechanism having a conditioning element for conditioningthe polishing surface; and a station disposed laterally from thepolishing surface and beneath the non-conditioning position of theconditioning element, the station comprising: a body; a first sensorcoupled to the body and configured to detect a first position of theconditioning element; and a second sensor coupled to the body andconfigured to detect a second position of the conditioning element. 14.The system of claim 13 further comprising: a nozzle disposed in thestation and arranged to direct a fluid to a bottom surface of theconditioning element.
 15. The system of claim 14 further comprising: athird sensor configured to provide a metric indicative of a fluid flowthrough the nozzle.
 16. The system of claim 14 further comprising: athird sensor configured to provide a metric indicative of downforce ofthe conditioning element.
 17. The system of claim 14 further comprising:a third sensor configured to provide a metric indicative of rotation ofthe conditioning element.
 18. A rinse station for a conditioningmechanism, comprising: a body configured to engage with a conditioningelement of a conditioning mechanism; a rinse nozzle disposed in the bodyand configured to spray a fluid on the conditioning element when engagedwith the rinse station; and at least one sensor coupled to the body andconfigured to detect an performance attribute of the conditioningelement.
 19. The rinse station of claim 18, wherein the at least onesensor further comprises at least one of a force sensor, a flowdetection sensor, a cut-rate sensor, a rotation sensor, or a sensorsuitable for providing an image of the conditioning element.
 20. Therinse station of claim 18, wherein the at least one sensor furthercomprises: a first sensor configured to detect the first position of theconditioning element; and a second sensor configured to detect thesecond position of the conditioning element.
 21. A semiconductorsubstrate polishing system having a polishing surface, comprising: aconditioning mechanism movable between a conditioning position disposedover the polishing surface and a non-conditioning position to the sideof the polishing surface, the conditioning mechanism having aconditioning element for conditioning the polishing surface; a rinsestation disposed laterally from the polishing surface and beneath thenon-conditioning position of the conditioning element, the rinse stationcomprising: a body; a rinse arm having a nozzle configured to spray afluid on the conditioning element; a first sensor coupled to the bodyand configured to detect a first position of the conditioning element;and a second sensor coupled to the body and configured to detect asecond position of the conditioning element; and a controller coupled tothe first sensor and the second sensor, the controller containinginstructions to characterize the motion of the conditioning element. 22.A method for characterizing a component of a conditioning mechanism,comprising: actuating a conditioning element of the conditioningmechanism to move between a first position and a second position; andanalyzing an actuation time required to move the conditioning elementbetween the first position and the second position.
 23. The method ofclaim 22, wherein the analyzing step further comprises: comparing theactuation time to a predetermined time.
 24. The method of claim 22,wherein the analyzing step further comprises: determining, from trendsor deviations form a historical database of actuation times, a need toservice the conditioning mechanism.
 25. A method for characterizing acomponent of a conditioning mechanism, comprising: interfacing aconditioning mechanism disposed in a non-conditioning position with oneor more sensors; obtaining a metric indicative of conditioning mechanismperformance from the one or more sensors; and determining if the metricof performance is within a process window.
 26. The method of claim 22,wherein the obtaining the metric indicative of conditioning mechanismperformance further comprises: detecting a rotation of the conditioningmechanism.
 27. The method of claim 22, wherein the obtaining the metricindicative of conditioning mechanism performance further comprises:detecting a flow of a cleaning fluid into the conditioning mechanism.28. The method of claim 22, wherein the obtaining the metric indicativeof conditioning mechanism performance further comprises: detecting adownforce of the conditioning mechanism.
 29. The method of claim 22,wherein the obtaining the metric indicative of conditioning mechanismperformance further comprises: detecting a cut-rate of the conditioningmechanism.
 30. The method of claim 22, wherein the obtaining the metricindicative of conditioning mechanism performance further comprises:evaluating a conditioning surface of a conditioning element of theconditioning mechanism.